2-chloro-5-isopropylphenyl n-chloroacetyl-n-methylcarbamates and their use as pesticides



methylcarbamate.

United States Patent 3,402,247 2-CHLORO-S-ISOPROPYLPHENYL N-CHLOROACE- 'TYL-N-METHYLCARBAMATES AND THEIR USE AS PESTICIDES Albert H. Haubein, Newark, Del., assignor to Hercules Incorporated, Wilmington, DeL, a corporation of Delaware No Drawing. Filed Feb. 27, 1967, Ser. No. 619,029 10 Claims. (Cl. 424300) ABSTRACT OF THE DISCLOSURE The compounds are of the class of substituted-phenyl carbamates, useful as insecticides. A representative compound is 2-chloro-5-isopropylpl1enyl N-chloroacetyl-N- This invention relates to new compositions of matter. More particularly, it relates to 2 chloro isopropylphenyl N-chloroacetyl-N-methylcarbamates and to their use as pesticides.

It has been found in accordance with the present invention that 2-chloro-S-isopropylphenyl N-chloroacetyl-N- methylcarbamates which conform to the structural formula:

CH3 CHa--H wherein n represents the integer 1, 2 or 3, are new compounds which are highly toxic to insects contacted therewith and are relatively non-toxic to mammals.

These chloroacetyl-N-methylcarbamates may be prepared by effecting reaction between a metal salt of the 2-chloro-S-isopropylphenyl N-methylcarbamate and the appropriate acid chloride (Stefanye et al., J. Am. Chem. Soc., vol. 77 (1955), pages 3663 4). They also may be prepared by reaction of 2-chloro-5-isopropylphenyl chlorocarbonate with the appropriate N-methyl chloroacetamide. Furthermore, the 2-chloro-5-isopropylphenyl N- chloroacetyl-N-methylcarbamate can be prepared from the corresponding N-methylcarbamate and chloroacetic anhydride. The preferred method, however, comprises heating the 2-chloro-S-isopropylphenyl N-methylcarbamate with the corresponding substituted acetyl chloride, in which reaction hydrogen chloride is evolved. An inert solvent of suitable boiling range, such as toluene or xylene, may be utilized, if desired. The temperature of this reaction should be sufficiently high to cause hydrogen chloride formation but not so high as to cause product decomposition. A preferred reaction temperature range is from about 100 C. to about 140 C. Preparation of the subject compounds is illustrated by the following example, all parts and percentages specified being by Weight.

Example 1 A mixture of 100 parts 2-chloro-5-isopropylphenyl N- methylcarbamate and 75 parts chloroacetyl chloride was heated at reflux, about 110 C., While slo'wly sparging with nitrogen. Heating was continued until only a small amount of hydrogen chloride gas was detected in the offgas. During this time the reaction temperature increased, but was not allowed to exceed 130 C. Excess ch1oro acetyl chloride was removed by vacuum distillation at 0.5 mm. pressure and a pot temperature which reached 100 C. The dark liquid residue which remained comprised 142 parts 2-chloro-5-isopropylphenyl N-chloroacetyl-N-methylcarbamate, and analyzed 23.9% C1 compared to the theoretical value of 23.3%. By infrared absorption analysis, the product was found also to contain only a small amount (3.5%) of unreacted 2-chloro-5-isopropylphenyl N-methylcarbamate.

The other two compounds of this invention are prepared following the procedure of Example 1. Dichloroacetyl chloride is used in the preparation of 2-chloro-5- isopropylphenyl N dichloroacetyl N methylcarbamate, and trichloroacetyl chloride is utilized in the production of 2 chloro 5 -isopropylphenyl N-trichloroacetyl-N-methyl carbamate.

Biological tests were carried out using aqueous dispersions of 2-chloro-5-isopr0pylphenyl N-chloroacetyl-N- methylcanbamate as insecticide sprays to demonstrate that these carbamates are toxic to a variety of undesirable pests. The sprays employed were prepared by adding to solutions comprised of about equal parts of active compound, benzene, and Tween 20 (a sorbitol monolaurate polyoxyethylene derivative), suflicient quantities of distilled water to result in aqueous dispersions of various toxicant concentrations.

The compound 2-chloro-5-isopropylphenyl N-chloroacetyl-N-methylcarbamate was only partially effective when used at a concentration of 1% against Southern armyworms. However, the compound produced high mortality in pea aphids at concentrations of 0.1% and 0.05%. Against houseflies, the compound was moderately effective when applied as a spray containing 0.1% of toxicant.

Mexican bean beetles were quite susceptible, concentrations of 0.01% and 0.005 of the compound being capable of producing a very high proportion of fatalities. Also, the compound was active against corn rootworm larvae, providing high mortality at a concentration of 0.01%.

While he preceding information indicates generally the pesticidal utility of the subject carbamates, their most notable utility has been found to be as insecticides for the control of adult mosquitoes. It is in the use of these compounds as adult mosquitocides that the most beneficial embodiment of the present invention resides.

To be classified as a good adult mosquitocide, a compound should not only demonstrate a high degree of initial toxicity, but also toxicity which persists at a relatively undiminished level for a period of days or preferably weeks. The test method used to demonstrate the outstanding initial and residual toxicity of the present chloroacetyl-N-methylcarbamates, and the data obtained, are given in the following example.

Example 2 An aqueous emulsion containing 0.25% of the toxicant to be tested was pipetted into a non-porous un- Waxed paper cup in an amount sufficient to cover the surface thereof with either 50 mg. or 25 mg. of toxicant per square foot; which emulsion was spread all over the inner surface until dry. The treated cups were allowed to stand open for one to three days at ambient conditions of about 78 C. to 50% relative humidity. Ten female, unfed, adult mosquitoes, anesthetized with CO were placed on an l8-mesh stainless steel wire screen and covered by 21 treated cup, the screen being open to the atmosphere. The mosquitoesrevived in a few minutes and were allowed to walk on the walls of the cup for about one hour. They were again anesthetized with CO and were placed into a 5-inch circular cage of 14- mesh stainless steel and given food and water. The percent dead after 24 hours was then determined. A fresh group of mosquitoes was placed in the same cup a number of days later and the toxic effect again determined as above. This procedure was repeated at various time J intervals until an appreciable drop in toxicity was noted. pesticides are applied, through the use of surface-active The following data were recorded: agents when necessary, there may be circumstances un- ADUL'I WOSQUITO TEST 1 Weeks (after treatment of cup) Concentration 2-eh ore-- isopropylpheuylN-ehloro- 1 3 5 7 9 11 12 13 15 17 19 20 cetyl N-rnethylcarbamate (mgnlsq. it.) Percent Kill 50 100 100 100 100 90 100 100 100 100 100 100 70 2s 100 100 100 so 90 100 90 70 60 50 0 Ideally, pesticidal compounds will be relatively harmder which it is desired to omit such agents; such cases less to mammals and yet highly toxic to undesirable are also intended to be within the scope of this invenpests. Acute oral toxicity to White rats is a measure of 15 tion. Toxicant concentrations in these extended formulaharm to mammals, such toxicity often being expressed tions may vary within wide limits; suitable concentrain terms of LD values. The LD value assigned to a tions for application in the field range from about 0.01% compound expresses the amount of that compound, in to about 20% of toxicant based on the total weight of mg. per kg. of body weight, which will be a lethal dose formulation. to 50% of the animals tested, a high LD value indicat- 20 The aqueous dispersions contemplated herein coming a low (favorable) mammalian toxicity since a large prise a compound of this invention, water and a surfacedose is required. The compounds of this invention have active dispersing agent. Ordinarily an aqueous dispersion high LD values and are highly suitable for use proxiwill be made up from a concentrate comprised of the mate to mammals. toxic compound and a surface-active agent, which con- The compounds of the present invention may be emcentrate will subsequently be dispersed in water to a deployed alone or together in pesticidal formulations as sired concentration. The amount of toxic compound conthe sole toxicants thereof. Alternatively, properties of tained in a spray properly diluted for application in the these compounds may be modified by employing them in field will generally range from about 0.01% to about admixture with other toxicants such as toxaphene, DDT, 20% of such an aqueous dispersion. In most instances, Thanite, Chlordane, rotenone, pyrethrum, and the like. the amount of surface-active agent used will be from These earbamates are applied according to any of about 1% to about 25% of the amount of toxicant the methods suitable for pesticide application, for eX- present. Organic solvents may also be contained in the ample, as solvent solutions or in combination with solid concentrate to aid in effective dispersion. or liquid extenders or adjuvants. Suitable solvents for Suitable surface-active dispersing agents for use in the the preparation of solvent solutions, which may either be compositions of this invention are those disclosed in used directly or after dispersion in an immiscible liquid Chemistry of Insecticides, Fungicides, and Herbicides or on a solid carrier, include pine oil, alcohols, hydro- (Donald E. H. Frear, second edition (1948), pages 280- earbbn Solvents Slleh as Xylene, methylated naphthalene, 287) for use with known insecticides. They include neutral and iSOPhOYOHe, diiillol'bdiehioromethane, deOfiOriZed soaps of resin, alginic, and fatty acids, with alkali metals, kerosene, eyeibhexahone, methyl isobutyl ketbne, and alkyl-amines or ammonia; saponins, gelatins, milk, other Similar Organic sbivehtswhen Such a Solvent sbiusoluble casein, flour and soluble proteins thereof, sulfite tion is to be used directly, the concentration of toxicant l lignin itch, sulfite liquor, long-chain fatty alcohols Contained therein y range from about 10% to about having 12-18 carbon atoms and alkali metal salts of the 90% based on the Weight of e soiiltibn- QtheY'WiSe, the sulfates thereof, salts of sulfated fatty acids, salts of sultoxicant concentration in solution will be ad usted so f i id esters f1o h i fatty id and l h that upon further dilution the desired ultimate conceni alcohols ih'which alcohol groups are free, Solid i tration results. Amounts of toxicant ranging from about persahts such as f ll earth, China Clay, kaolin,

to about 10% y Weight of the diiuted formulapulgite, and bentonite and related hydrated aluminium tion have generally been found to be sultabie' silicates having the property of forming a colloidal gel. ample Of all application in which a sbivent soiutioi} can Among the other surface-active dispersing agents which be used directly is Where the tQXlealit is e e iii an are useful in the compositions of this invention are the aerosol formulation, in which case difiuorodichloroomega substhuted polyethylene glycols of relatively long methane or a similar aerosol propellant functions, both chain length, Particularly those in which the omega as the solvent and as the propellant vehicle. shtueht is al-yl, alkyl, or acyl,

in y instances it Wi be t aivantageous, for Compositions of the toxic material and surface-active reasons of eeohbiny, iiaeiiity 9 appiic'fiition: t to dispersing agent will in some instances have more than ploy these pestlcides in admixture with solid or 11011- one surface-active dispersing agent for a particular type solvent liquid extenders. Such extenders include water of utility For example, the toxic material may Contain and solid carrier materials, preferably those that are surface active clay as the sole adj-Want or clay and readily available and inexpensive F as talc attapul another surface-active dispersing agent to augment the g natural y Py p dlatomaceous earth dispersing action of the clay. Similarly, as is hereinbefore kaolin, aluminum and magnesium silicates, montmorillonite, and similar substances such as are used as carriers in the insecticide and herbicide arts. Using such solid materials as extenders, wettable powders and dusts may be formulated. In many instances, the extenders envisioned for use in this invention will themselves possess surface-active properties, in which case they may properly be termed dispersants. In other instances, such as when water is used, the extender possesses no surfaceactive properties of its own, and an additional material described, the toxic material may have Water admixed therewith along with a surface-active dispersing agent, most often the amount of water added being suffieient to form an emulsion. All of these compositions comprising toxic compounds and surface-active dispersing agents may contain, in addition, synergists and/ or adhesive or sticking agents. Moreover, the recital of specific classes of additives is not intended to limit the scope of this invention thereto, but it is to be understood that the addition ill b dd d to i i h dispersion f the toxicant of other materials of these formulations is also envisioned. throughout the extender. It should be realized that while In Using the tOXieahtS of this invention for killing P it is generally advantageous to distribute as uniformly as the compounds act by contact therewith, which contact possible the toxic substances over surfaces to which the may be direct, as by spraying the insects themselves, and/ wherein n represents an integer selected from the group consisting of 1, 2 and 3.

2. A composition in accordance with claim 1 wherein n represents the integer 1.

3. A composition in accordance with claim 1 wherein n represents the integer 2.

4. A composition in accordance with claim 1 wherein n represents the integer 3.

5. A composition capable of pesticidal activity when dispersed comprising a compound of claim 1 in admixture with a surface-active dispersant.

6. A composition capable of pesticidal activity comprising a compound of claim 1 dissolved in a solvent therefor.

7. A composition capable of pesticidal activity comprising a minor amount of a compound of claim 1 and a major amount of water.

Cln

8. A composition capable of pesticidal activity comprising a minor amount of a compound of claim 1 and a major amount of a solid carrier material.

9. The method of killing insects which comprises contacting said insects with a toxic amount of a compound of claim 1.

10. The method in accordance with claim 9 in which said insects are mosquitoes.

References Cited UNITED STATES PATENTS 3,341,401 9/1967 Kilsheimer et a1 167-30 FOREIGN PATENTS 912,356 12/1962 Great Britain. 982,235 3/1965 Great Britain.

OTHER REFERENCES Fraser et al., J. Sci. Fd. Agric. 16: 615-618, October 1965, N-Acylation of N-Methylcarbamate Insecticides and Its Effect on Biological Activity.

Reay et al.; J. Sci. Fd. Agric. 17: 17-19, January 1966, Evidence for Difierences in Mode of Action Between Two Related Carbamate Insecticides.

'L'EWIS GOTTS, Primary Examiner. S. K. ROSE, Assistant Examiner. 

